feat: Add ability to remove bytes (#531)

Co-authored-by: Dmitry Polshakov <dmitry.polshakov@dsr-corporation.com>

lib/libimhex/include/hex/providers/provider.hpp

@@ -35,6 +35,7 @@ namespace hex::prv {
 
         virtual void resize(size_t newSize);
         virtual void insert(u64 offset, size_t size);
+        virtual void remove(u64 offset, size_t size);
 
         virtual void save();
         virtual void saveAs(const std::fs::path &path);

lib/libimhex/source/providers/provider.cpp

@@ -63,6 +63,22 @@ namespace hex::prv {
             patches.insert({ address + size, value });
     }
 
+    void Provider::remove(u64 offset, size_t size) {
+        auto &patches = getPatches();
+
+        std::vector<std::pair<u64, u8>> patchesToMove;
+
+        for (auto &[address, value] : patches) {
+            if (address > offset)
+                patchesToMove.emplace_back(address, value);
+        }
+
+        for (const auto &[address, value] : patchesToMove)
+            patches.erase(address);
+        for (const auto &[address, value] : patchesToMove)
+            patches.insert({ address - size, value });
+    }
+
     void Provider::applyOverlays(u64 offset, void *buffer, size_t size) {
         for (auto &overlay : this->m_overlays) {
             auto overlayOffset = overlay->getAddress();

plugins/builtin/include/content/providers/file_provider.hpp

@@ -32,6 +32,7 @@ namespace hex::plugin::builtin::prv {
 
         void resize(size_t newSize) override;
         void insert(u64 offset, size_t size) override;
+        void remove(u64 offset, size_t size) override;
 
         void readRaw(u64 offset, void *buffer, size_t size) override;
         void writeRaw(u64 offset, const void *buffer, size_t size) override;

plugins/builtin/source/content/providers/file_provider.cpp

@@ -123,7 +123,7 @@ namespace hex::plugin::builtin::prv {
 
         auto position = oldSize;
         while (position > offset) {
-            size_t readSize = (position >= (offset + buffer.size())) ? buffer.size() : (position - offset);
+            const auto readSize = std::min<size_t>(position - offset, buffer.size());
 
             position -= readSize;
 
@@ -135,6 +135,28 @@ namespace hex::plugin::builtin::prv {
         Provider::insert(offset, size);
     }
 
+    void FileProvider::remove(u64 offset, size_t size) {
+        auto oldSize = this->getActualSize();
+        this->resize(oldSize + size);
+
+        std::vector<u8> buffer(0x1000);
+
+        const auto newSize = oldSize - size;
+        auto position = offset;
+        while (position < newSize) {
+            const auto readSize = std::min<size_t>(newSize - position, buffer.size());
+
+            this->readRaw(position + size, buffer.data(), readSize);
+            this->writeRaw(position, buffer.data(), readSize);
+
+            position += readSize;
+        }
+
+        this->resize(newSize);
+
+        Provider::insert(offset, size);
+    }
+
     size_t FileProvider::getRealTimeSize() {
 #if defined(OS_LINUX)
         if (struct stat newStats; (this->m_fileStatsValid = fstat(this->m_file, &newStats) == 0)) {

plugins/builtin/source/content/views/view_hex_editor.cpp

@@ -328,6 +328,37 @@ namespace hex::plugin::builtin {
         u64 m_size;
     };
 
+    class PopupRemove : public ViewHexEditor::Popup {
+    public:
+        PopupRemove(u64 address, size_t size) : m_address(address), m_size(size) {}
+
+        void draw(ViewHexEditor *editor) override {
+            ImGui::TextUnformatted("hex.builtin.view.hex_editor.menu.edit.remove"_lang);
+
+            ImGui::InputHexadecimal("hex.common.address"_lang, &this->m_address);
+            ImGui::InputHexadecimal("hex.common.size"_lang, &this->m_size);
+
+            View::confirmButtons("hex.builtin.common.set"_lang, "hex.builtin.common.cancel"_lang,
+                [&, this]{
+                    remove(this->m_address, static_cast<size_t>(this->m_size));
+                    editor->closePopup();
+                },
+                [&]{
+                    editor->closePopup();
+                });
+        }
+
+    private:
+        static void remove(u64 address, size_t size) {
+            if (ImHexApi::Provider::isValid())
+                ImHexApi::Provider::get()->remove(address, size);
+        }
+
+    private:
+        u64 m_address;
+        u64 m_size;
+    };
+
     ViewHexEditor::ViewHexEditor() : View("hex.builtin.view.hex_editor.name") {
         this->m_currDataVisualizer = ContentRegistry::HexEditor::impl::getVisualizers()["hex.builtin.visualizer.hexadecimal.8bit"];
 
@@ -1373,6 +1404,10 @@ namespace hex::plugin::builtin {
             if (ImGui::MenuItem("hex.builtin.view.hex_editor.menu.edit.insert"_lang, nullptr, false, providerValid && provider->isResizable())) {
                 this->openPopup<PopupInsert>(this->getSelection().getStartAddress(), 0x00);
             }
+
+            if (ImGui::MenuItem("hex.builtin.view.hex_editor.menu.edit.remove"_lang, nullptr, false, providerValid && provider->isResizable())) {
+                this->openPopup<PopupRemove>(this->getSelection().getStartAddress(), 0x00);
+            }
         });
     }
 

plugins/builtin/source/lang/en_US.cpp

@@ -278,6 +278,7 @@ namespace hex::plugin::builtin {
                     { "hex.builtin.view.hex_editor.menu.edit.set_base", "Set base address" },
                     { "hex.builtin.view.hex_editor.menu.edit.resize", "Resize..." },
                     { "hex.builtin.view.hex_editor.menu.edit.insert", "Insert..." },
+                    { "hex.builtin.view.hex_editor.menu.edit.remove", "Remove..." },
 
                 { "hex.builtin.view.information.name", "Data Information" },
                     { "hex.builtin.view.information.control", "Control" },